Compressor muffler construction and method for



Nov. 5, 1963 K. M. GIERTE'IS 3,109,584

COMPRESSOR MUFFLER CONSTRUCTION AND METHOD FOR MUFFLING COMPRESSOR DISCHARGE GASES 2 Sheets--Sheet 1 Filed March 13, 1958 INVENTOR. KARL M GE/PTE/S ATTORNEY Nov. 5, 1963 K. M GERTEIS 3,109,584

COMPRESSOR MUFF C ONSTRUCTION AND METHOD FOR .MUFFLING C RESSOR DISCHARGE GASES Filed March 13, 1958 2 ShGGtS-ShBBi 2 INVENTOR.

KARL M. GERTEIS BY WM A TTORNE Y United States Patent CQMPRESSOR MUFFLER (JQNSTRUCTION AND METHOD FOR lviUFFLIPJG COMPRESSOR DIS- CHARGE GASES Karl M. Gerteis, Syracuse, FLY, assignor to Carrier Corporation, Syracuse, NFL Z, a corporation of Delaware Filed Mar. 13, I958, Ser. No. 721,227 2 Claims. (Q1. 230-232) This invention relates to reciprocating compressors and, more particularly, to reciprocating compressors having mufiier constructions for discharge gases. This invention also relates to a method of muifling the discharge gases of a compressor.

Compressors, and especially compressors in refrigeration systems, are steady sources of sound energy, a portion of which appears as sound waves transmitted from the discharge section of the compressor. This sound energy appears both as kinetic energy and potential energy. The kinetic energy is the result of an instantaneous velocity of slugs or pulsations of gas, and the potential energy is in the form of stored energy manifesting itself in the vibration of any elastic enclosing elements.

In a refrigeration system these sound waves generally originate from the discharge line and the condenser of the refrigeration system associated with the compressor. These sound waves give rise to airborne noises which emanate from the containing walls holding the gas which are caused to vibrate. T'hcse noises are initially created by the pulsating nature of the gas supplied by the reciprocating compressor. These streams of gas in the form of pulsations, are followed by low pressure conditions which cause a reverse flow of the gas creating a standing wave which is intercepted by the next pulsation causing a substantial level of noise. This sound is then conducted through the containing walls and becomes airborne. Simultaneously the energy generated by the collision of gas slugs causes vibration of the containing walls causing further airborne noise.

The present invention envisions solving this problem by the provision of a structure whereby airborne noise is minimized and the pulsating nature of the gas discharge from the compressor is diminished in an inexpensive manner with a minimum pressure drop through the mutfling element.

The chief object of the present invention is to provide a construction which diminishes the noise resulting from the pulsating nature of the discharge of reciprocating compressors, with a minimum pressure drop and in a manner whereby the discharge line of the compressor is not a significant source of airborne noise.

Another object of the invention is to provide an inexpensive cast iron muffler structure to be bolted to the compressor block.

A further object is to provide an integral muffler which is bolted with the head of the compressor to the compressor block.

A further object is to provide a method for substantially mufiling the discharge gas from a reciprocating compressor with a minimum pressure drop and in a manner whereby the discharge line from the compressor is not a significant source of airborne noise.

A still further object is to provide a cast rnufiler for a reciprocating compressor providing a low pass acoustical filter which absorbs vibration causing noises and simultaneously subjects the gases passing therethrough to a minimum pressure drop. These and other objects of the invention will become more apparent from the following description.

This invention relates to a reciprocating compressor comprising a plurality of cylinders, having a plurality of ildiifidd Patented Nov. 5, 19:63

cylinder heads associated therewith and a manifold placing said cylinders in communication, said manifold being located in the compressor block. Means defining a discharge gas opening is placed in communication with the manifold and a cast mufiier is bolted to the compressor block and connected to said discharge gas opening. The muffler includes first, second and third spaces connected by suitable venturis, thereby constituting an acoustical low pass filter.

This invention also relates to a method for muffiing the discharge gases from a reciprocating compressor which consists in the steps of expanding the gas in a first space, passing the gas through a first venturi, expanding the gas in a second space, passing the gas through a second venturi and then expanding the gas in a third space to substantially remove the pulsating nature of the gas.

The attached drawings illustrate preferred embodiments of the invention in which FIGURE 1 is a side view of the compressor incorporating the present inwention,

FIGURE 2 is an end view of the compressor shown in FIGURE 1, partially in section to illustrate the cylinder and manifold orientation,

FIGURE 3 is an enlarged sectional view taken along the line 3-3 in FIGURE 1,

FIGURE 4 is a sectional view taken along the line 4-4 in FIGURE 3,

FIGURE 5 is a side view of a compressor incorporating another embodiment of the invention,

FIGURE 6 is an end view of FIGURE 5, partially in section to illustrate the cylinder and manifold orientation,

FIGURE 7 is an enlarged sectional view taken along the line 7-7 in FIGURE 5, and

FIGURE 8 is a sectional view taken along the line 38 in FIGURE 7.

Referring to the drawings there is shown in FIGURE 1 a side view of a hermetic compressor having a W cylinder orientation. The compressor comprises a compressor block 2 having a motor housing section 3 and a compression equipment section 4. Located at the side of the compressor is a juncture box 5 which is provided to supply electric current to the motor of the compressor. In the lower portion of the compression section of the block is located an access opening having a cover 6. At the upper portion of the compressor is located a muffier 7 which will be described more fully hereinafter.

FIGURE 2 illustrates an end view of the compressor shown in FIGURE 1 having a section thereof removed to disclose the inner sections of the compressor comprising a portion of the present invention. FIGURE 2 illustrates the W configuration of the cylinders 10, 11 and 12. Located in these particular cylinders are the pistons 13. 14 and 15. It will be appreciated that if desired, each section of the W may comprise a plurality of cylinders.

Located above the cylinder 10, is a cylinder head 17, and above the cylinder 12, the cylinder head 18. The cylinder heads 17 and 18 are similar in shape. Located above the cylinder 11 is the cylinder head 19 which differs from the cylinder heads 17 and 18 in that the upper portion of the cylinder head 19 is provided with a sealing surface adapted to engage the muffler 7 in sealing contact. The muffler and the cylinder head are attached by suitable bolt connections to the compressor block 2, these bolts being fitted into recesses in the mufiier, passing therethrough and engaging threaded portions in the compressor block.

Valve assemblies 20, 21 and 22 are disposed between the cylinder heads and the cylinders. These valve assemblies function in a well known manner whereby suction gas may be introduced into the cylinder and then the compressed gas is discharged through the valve as- 3 sernbly into the cylinder heads to be ultimately discharged from the compressor.

The valve assembly 20 located below the cylinder head 17 is provided With a suitable opening 23 and the valve assembly 22 located below cylinder head 18 is provided with a similar opening 24. These openings place the cylinder heads 17 and 18 into communication with the manifold consruction provided integrally in the compressor block. These manifold sections 25 and 26, respectively, placethe cylinder heads 17 and 13 into communication by means of the openings 27 and 28 in the valve assembly 21 with the cylinder head 19. Compressed refrigerant gas in cylinder 11 is discharged through the valve plate 21 into the cylinder head 19 and joins the gases from the cylinder heads 17 and 18.

These gases are then discharged through the opening 30 in the cylinder head 19 into the muffier 7. FIGURE 3 is an enlarged sectional view of the mufiler taken along the line 33 shown in FIGURE 1. It is noted that the muffler 7 has a general elliptical profile substantially the same as the elliptical profile of the cylinder head 19. This elliptical profile provides the outer wall 32 of the mufiler. It will be noted that this elliptical wall has a general undulating interior surface which is the result of the provisions made for bolt holes 33 passing through the muffier body.

FIGURE 4 illustrates a sectional view of one of the bolt sections taken along the line 44 in FIGURE 3. It will be noted that the mufiler 7 is provided with a recessed portion 35 into which is placed the head of the bolt 40. The bolt 40 passes through the cylinder head 19, the valve plate 21, and is adapted to engage the compressor block 3. Suitable sealing gaskets 36, 37 and 38 are placed between the elements. By this type connection the valve plate, cylinder head and mufiler are attached to the compressor block.

Referring again to FIGURE 3, it will be noted that a partition 42 defines a first space 43 into which the opening 30 in the cylinder head 19 discharges. In the partition 42 there is located an orifice 44 having a general venturi shape which is defined generally by the walls 45. A venturi as used herein consists of means defining a short passage with flaring ends and a constricted connecting opening. The partition 42 and the outer wall 32 combine with a second partition 47 to form a second space 48. Located in the second partition is a second orifice 49 having a general venturi shape generally defined by the walls 50. This venturi discharges into a third space 51 which is located at the opposite end of the muffler from the space 43. The mufiier 7 is provided with a discharge opening 52. Because of symmetry and the need for adequate bolting to unite the muffier to the compressor body it is necessary to provide a suitable member 53 in the discharge opening 52. This member 53 is provided with an opening therein for a bolt to pass therethrough. It will be noted that this member has a general tear drop shape so as to afford a minimum resistance to the gases passing through the opening 52. For reasons to be disclosed hereinafter the muffler .7 is cast and is fabricated preferably of cast iron.

FIGURE discloses another embodiment of the present invention. The compressor illlstrated is of a V cylinder type comprising a compressor block 60 having a motor section 61 and a compression section 62, suction gas being introduced from the suction gas inlet 63 on the motor side of the block. On the side of the compressor is located a juncture box for making the electrical connections to the motor of the compressor. At the lower area of the compression section is located an access opening having a cover 65, located in the upper portion of the compression section is the muffler 66.

FIGURE 6 shows an end view of the compressor illustrated in FIGURE 5 wherein a portion is shown in section mentioned before a plurality-of cylinders may be used in each side of the V. Located above the cylinders are the valve assemblies 72 and 73 and located above these valve assemblies are the cylinder heads 74 and 75.

In a manner similar to that utilized in the previous embodiment the valve plate assemblies 72 and 73 are provided with openings 72 and 73' which place the cylinder heads 74 and 75 into communication with the manifold sections 76 and 77. These manifold sections meet at a central portion of the cylinder block and are in communication with the discharge opening 78. The mufiler 66 is shown bolted to the compressor and is connected to the discharge gas opening 78.

Referring to FIGURE 7 there is shown a sectional view of the muffler used in FIGURE 5 taken along the line 77. The muifier comprises a generally cylindrical member 80 including an internal partition section 81 having enlarged portions to provide space for the bolt openings 82. The partition 81 defines a first space 84 which is connected to the compressor by means of the discharge gas opening 78.

At one end of the muffler, the partition 81 and the housing 8% define a second space 85 which is placed in communication with the first space 84 by means of a venturi 83. This second space is placed in communication with a third space 89, located at the opposite end of the mufiler by means of the venturis 87 and 88 which are defined by portions of the partition 81 and the housing 80 and are located in a parallel relationship on either side of the partition 81. The third space discharges through the discharge opening 90.

The muffler 66 is attached to the compressor by means of suitable bolts passing through the openings 82 shown in FIGURE 7. FIGURE 8 shows a sectional view of one of the bolt connections taken along the line 8-8 shown in FIGURE 7. This sectional view shows a recessed portion 91 located in the mufiler 66. The bolt 92 is passed through the mufiler body and engages the compressor block 60. Located between the compressor block and the mufller is a suitable gasket 93 to insure good sealing engagement between the muffler and the body of the compressor.

Considering the operation of the present invention, referring to the embodiment shown in FIGURES 1, 2 and 3, gases compressed in the cylinders 10, 11 and 12 discharge through the various valve plates in a conventional manner and then pass into the cylinder heads 17, 1'8 and 19. The gases in the cylinder heads 17 and 18 pass through the openings 23 and 24 in the valve plate assemblies. The gas is then passed thnough the manifold sections 25 and '26 and through the openings 27 and 28 in the valve plate 21. Simultaneously the cylinder 11 discharges through the valve plate 21 into the cylinder head 19. It will be noted at this point that the discharge gases from all these cylinders ultimately pass into the cylinder head 19. The gas is then passed through the discharge opening in the cylinder head 19 and referring to FIGURE 3, the gas passes upwardly into the mufller 7 in a surge reflecting the pulsating nature of the gas supply from the various cylinders. This surge of gas is then ex panded in the first space 43. It Will be appreciated at this point that because the mufiler is so close to the source of the pulsating gas there is little opportunity to create airborne noises. The pulsating gas as it enters the first space 43 is suitably expanded and because the cast iron construction provides heavy retaining Walls there is little transmittal of vibration through the muffler body itself. The sound is substantially dampened. The discharge gases in the first space 43 are then discharged through the first venturi 44 into the second. space 48. The venturi shape of the orifice provides an extremely efiicient discharge opening and causes a diffusion action into the second space. This same action is then repeated through the second venturi 49, into third space 51. At this point the pulsating character of the gases has been suitably dirninished. The gas is then discharged through the opening 52 and into the discharge line of the refrigeration system.

The mufiier construction in FIGURE 3 is a form of an acoustical low pass filter. The spaces 43, 4 8 and 51. provide an acoustical capacitance which is equivalent to an electrical analogy of an electrical capacitance and the venturis create an inertance which is acoustically equivalent to an electrical inductance. This acoustical mufl'ling system is substantially equivalent to its electrical analogy of a low pass filter.

The surging gas as it enters the first space is subjected to the acoustical capacitance wherein the gases are expanded therein. The gas is then passed through the inertance wherein the pulsating nature of the gas is diminished.

It will be noted, at this point, that it is normally suggested that an orifice be used as an inertance. However, it has been found that a venturi shaped orifice is more efficient in this application because of the lesser amount of energy expended passinggases through an orifice of this shape. The gas entering the venturi is first accelerated and then diffused into the next space. Furthermore, the pressure differential occurring across the venturi is such that the venturi acts as a check valve. As previously mentioned, one of the sources of noise in a compressor is the phenomenon that behind the surge of gas there is created a low pressure condition causing a standing wave which is intercepted by the next surge of gas causing a substantial amount of noise. By passing the gas into the first space and expanding therein, then passing the gas into the venturi, a large amount of the initial surge is lost. Because of the check valve action of the venturi, the effects of this standing wave interception phenomenon are greatly diminished. The gases discharged into the second space 48 are again expanded and then pass through the second venturi 49 until finally in the third space 51 the pulsating nature of the gas is substantially lost. It will be appreciated that because of the cast iron construction there is little opportunity for vibration of the containing body of the mufiier thereby diminishing the possibility of airborne noise. The gases passing into the discharge line connected to the discharge opening 52 have had most of the sound producing energy intercepted.

Referring to the second embodiment comprising the FIGURES 5, 6, and 7 gas is compressed in the cylinders 70 and 71 and discharged into the cylinder heads 74 and 75. This gas is directed through the openings 72' and 73' in the valve assemblies and is then passed through the manifold passages 76 and 77 located within the compressor block. These discharge gases are then passed through the opening 78 into the muffler 66. This action is essentially similar to that which occurred in the initial embodiment disclosed. However, the gases are not passed from the manifold into another cylinder head but rather directly into the muffler 66.

Referring to FIGURE 7, the gas is passed into the first space 84 where it is expanded and then passed through the venturi 83 into the second space '85. From the second space the gas is passed through the venturis 87 and 88 which act as an inertance to the sound and the gas is directed into the third space 89 and discharged through the opening 90 from the muffler. The sound dampening features of this particular mufller are essentially the same as those disclosed in FIGURE 3 with the exception that the path of the gases is different since the direction of the gas is changed 180 and also as the gas passes from the second space to the third space, it encounters two venturis before the gas passes into the third space 89.

The present invention provides an inexpensive and highly eifective manner for dampening and absorbing the kinetic and potential energy which originates from the compressor and finds its way into sound energy. The pulsating nature of the gas is intercepted at the earliest opportunity and because of the special acoustical low pass filter construction incorporating the unique venturis, a highly efficient vmufiler is provided which not only deadens the sound but also subjects the gas to a lesser pressure drop than is normally encountered. The extremely close proximity of the mufiler to the source of the sound furthermore diminishes the amount of airborne noise which is passed from the compressor and furthermore as a result of the cast iron construction of the mufller, the muffler itself is an insignificant source of vibration thereby providing a highly compact and inexpensive rnulfler construction.

While I have described the preferred embodiment of the invention it will be understoodthat the invention is not limited thereto so that it may be otherwise embodied in the scope of the following claims.

I claim:

1. A cast mufiier for a reciprocating compressor having a compressor block, a plurality of cylinders, a plurality of generally elliptical shaped cylinder heads associated with said cylinders forming spaces to receive compressed gas from said cylinders, means defining a manifold in said block placing the discharged gas spaces in communication with one another, and means defining a discharge gas opening in one of said heads in communication with the manifold, said discharge gas opening cooperating with the mufiler to define a chamber, said mufiier comprising a peripheral member having a generally elliptical shape, first and second partition means formed in said member, the wall of said member cooperating with said head containing the discharge gas opening and said first and second partition means to substantially define a first mufiler space at one end. of said member, a second muffler space in the center of said member between the first and second partition means and a third mufiler space at the other end of said member, a first venturi means placing said first and second muifier spaces into communication and second venturi means placing said second and third mufiler spaces into communication, the discharge gases being introduced into the first space through the means defining the discharge gas opening and means for discharging gases from said third space.

2. In a reciprocating compressor, the combination of a compressor block, a plurality of cylinders, a plurality of cylinder heads associated with said cylinders forming spaces to receive compressed gas discharged from said cylinders, means for placing the discharged gas spaces in communication, a cast mufiier housing open at an end having substantially the same profile as the cylinder heads, means engaging the block and passing through a cylinder head and the housing to attach said head and housing to the compressor block, said housing being in sealing engagement with said head, said head having a discharge opening therein to pass discharge gas from the compressed gas space in said head to said housing, said housing having partition means therein, the wall of said housing and the partition means cooperating with said cylinder head to define a first mufiler space, a second muffier space and a third muffler space, the discharge gas being introduced into said first muffler space, a first venturi placing said first and second rnufiier spaces in communication and a second venturi for placing said second and third mnfiier spaces in communication, each venturi comprising means defining a short passage with a flaring end and a constricted connecting opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,024,919 Waterous Apr. 30, 1912 1,663,998 Schmidt Mar. 27, 1928 1,682,316 Williams Aug. 28, 1928 1,990,837 Morgenstern Feb. 12, 1935 2,134,077 Ehret Oct. 25, 1938 (Other references on following page) :7 UNITED STATES PATENTS Feldbush et a1 Nov. 29, 1938 Hanson Nov. 7, 1939 Smith May 28, 1940 Chipley June 25, 1940 Bixler Nov. 26, 1940 Stephens Mar. 28, 1950 Bourne et a1. 2- June 27, 1950 Gamble Nov. 27, 1951 D012 Sept. 23, 1958 Wysong June 28, 1960 FOREIGN PATENTS France Sept. 24, 1925 France July 8, 1957 

1. A CAST MUFFLER FOR A RECIPROCATING COMPRESSOR HAVING A COMPRESSOR BLOCK, A PLURALITY OF CYLINDERS, A PLURALITY OF GENERALLY ELLIPTICAL SHAPED CYLINDER HEADS ASSOCIATED WITH SAID CYLINDERS FORMING SPACES TO RECEIVE COMPRESSED GAS FROM SAID CYLINDERS, MEANS DEFINING A MANIFOLD IN SAID BLOCK PLACING THE DISCHARGED GAS SPACES IN COMMUNICATION WITH ONE ANOTHER, AND MEANS DEFINING A DISCHARGE GAS OPENING IN ONE OF SAID HEADS IN COMMUNICATION WITH THE MANIFOLD, SAID DISCHARGE GAS OPENING COOPERATING WITH THE MUFFLER TO DEFINE A CHAMBER, SAID MUFFLER COMPRISING A PERIPHERAL MEMBER HAVING A GENERALLY ELLIPTICAL SHAPE, FIRST AND SECOND PARTITION MEANS FORMED IN SAID MEMBER, THE WALL OF SAID MEMBER COOPERATING WITH SAID HEAD CONTAINING THE DISCHARGE GAS OPENING AND SAID FIRST AND SECOND PARTITION MEANS TO SUBSTANTIALLY DEFINE A FIRST MUFFLER SPACE AT ONE END OF SAID MEMBER, A SECOND MUFFLER SPACE IN THE CENTER OF SAID MEMBER BETWEEN THE FIRST AND SECOND PARTITION MEANS AND A THIRD MUFFLER SPACE AT THE OTHER END OF SAID MEMBER, A FIRST VENTURI MEANS PLACING SAID FIRST AND SECOND MUFFLER SPACES INTO COMMUNICATION AND SECOND VENTURI MEANS PLACING SAID SECOND AND THIRD MUFFLER SPACES INTO COMMUNICATION, THE DISCHARGE GASES BEING INTRODUCED INTO THE FIRST SPACE THROUGH THE MEANS DEFINING THE DISCHARGE GAS OPENING AND MEANS FOR DISCHARGING GASES FROM SAID THIRD SPACE. 